A procedure has been developed for the accurate measurement of film and substrate optical
parameters from the multiple
sample single-wavelength ellipsometric data. The dimensional
reduction of the unknowns from
newly formulated ellipsometric functions, the root selection and
the thickness-dependent integer
deduction enhance the rapidity of finding solutions and the
convergence from a wide range of
initial guesses while avoiding undesirable solutions. An error
analysis carried out shows that the
procedure is very resistant to the propagation of angular errors
and allows the estimation of optimum film
thickness ranges under which the parameters can be
accurately found. The standard SiO2/Si
structure is particularly studied using the procedure that
is further illustrated with the experimental
data on Ni/BK7-glass structures. The SiO2 film
refractive index and thickness are thus shown to be accurately determined when sought along
with the substrate optical constants. Moreover, the film and substrate real indexes are not altered
in the presence of an interface layer between the film and the substrate while its existence is
indicated by a systematic lowering of the Si substrate extinction coefficient. The procedure can
be efficiently used in the continuous real-time optical characterization of films growing on
substrates.